Communication between diagnostic and/or therapeutic medical device implants within the body can be highly beneficial. One example is the information exchange between an implantable sensor and an implantable pulse generator (IPG), that uses the sensed information for optimizing its operation. Published U.S. Patent Application US 2004-0204744A1, which is incorporated by reference herein, discloses using an intra-body acoustic communication link for this purpose. As taught in that publication, in order to minimize energy consumption, the sensor implant is left deactivated (i.e., not powered on) until an acoustic wave pulse received from another implanted device activates the sensor implant using acoustic switch technology. Two possible transducer configurations applicable for this concept are disclosed in this published application.
Acoustic transducers integrated in implantable medical device are known. For example, U.S. Pat. No. 6,477,406, discloses several acoustic transducer configurations used for listening to sounds produced by the heart. However, these transducers were designed only for receiving acoustic signals, and not for transmitting acoustic signals. Moreover, the transducer configurations of this patent are optimized to low sound frequencies in a range of 5-300 Hz, while for acoustic communication much higher frequencies are used, e.g., in an ultrasonic range of 20 kHz-10 MHz. In particular, U.S. Pat. No. 6,477,406 does not teach an acoustic transducer that can effectively produce ultrasonic transmission or to serve as an effective receiver at high acoustic frequencies.
Acoustic communication was also suggested for data exchange between an implantable device and external unit, such as disclosed in U.S. Pat. No. 5,113,859. However, this patent also does not teach or describe an acoustic transducer capable of performing the communication, nor is there any transducer disclosed or described that is capable of transmitting ultrasonic signals at a level sufficient for activating an acoustic switch and or communicating with a second implant.